Focus on external threats from the Marathas and the British East India Company who took advantage of the Mughals’ weakening grip. They conquered territories which previously belonged to the Mughals.
Don’t forget economic decline! The Mughal revenue system couldn’t keep up with the growing expenses of the imperial court and military. They became heavily dependent on land revenue which decreased over time.
The Mughal Empire was basically on a decline from the death of Aurangzeb itself. Successive rulers were too occupied with their luxurious lives and harems to actually govern and tackle the challenges the empire faced.
Also mention the socio-religious tensions between Hindus and Muslims, and uprising from Hindu rulers which added fuel to the problems. But be objective and balanced in your analysis. All the best!